The answer will vary greatly depending on ones metabolism obviously, but take someone of average weight and metabolism, how long does it take for fat cells to begin building up in the body soon after eating fatty foods? What might the answer be for an athletic or sedentary person?
I think you’re a little confused. No fat will be stored if you’re eating fewer calories than you’re burning, and excess calories will be stored as fat regardless of what they came in as. Consumed fat can be stored as fat more quickly than consumed carbohydrates or protein, but it’s not like the body will automatically shun it as an energy source.
I don’t have any details on the time needed for storage, though.
You seem to be thinking that “fatty foods” make you fat. That’s a huge oversimplification.
Forgot that part, fat is stored if you’re consuming more calories then you’re burning. Lets assume someone is not excessing and consuming 2-3 times the normal recommended daily value. At what point does the body convert those calories into fat cells. A few hours, days?
Make that ‘exercising’.
On a molecular level, if you radiolabelled the lipids to determine the fate of the ingested molecules [I mean radioisotopes, like C-14, of course, not tiny transmitter collars), you’d see liver and fat cell uptake begin in minutes, and possibly seconds, especially if the intestinal absorption has been going on for a while. You have a limited volume of plasma (2.5-3L out of ~5L blood, so each gram of absorbed fat would equal a 25-30 mg/dL rise in serum levels) Overloading the blood with lipids would be problematic and unnecessary.
It really comes down to “where do you want the fat to be?” Plasma lipid binding proteins and liver-mediated responses can only rapidly accommodate so much. The fat still has to be somewhere. Cellular uptake is a standard response to rising blood levels of many substances. In many situations, adipocytes absorb fat more readily than they release it.